A new mapping tool developed by The Task Force for Global Health and its partners has helped Ethiopia and Tanzania reduce the number of districts needing mass drug administration for lymphatic filariasis (LF), saving an estimated $9.2 million in treatment costs.
As more countries move closer to reaching the 2020 elimination goal for LF, there is a growing need for new tools to understand when mass drug treatment (MDA) can be stopped, especially in low-prevalence settings. Stopping mass treatment too soon can cause a resurgence in the infection, while prolonging treatment after the disease has been eliminated can waste scarce resources.
The current World Health Organization (WHO) approach for mapping the prevalence of LF involves sampling 100 adults at two sites in each district. A finding of one of more confirmed positive tests at either site signals that MDA should be initiated.
“This approach works well for assessing whether to continue MDA in high-prevalence districts,” said Task Force epidemiologist Katie Gass, PhD, MPH. “But it is less reliable in low-prevalence settings where a single positive adult may not indicate that transmission is occurring and treatment should be continued.”
The new tool developed by Gass and her colleagues involves testing children 9-14 years old at different schools for evidence of LF infection. Children rather than adults are tested because recent studies suggest that infection among older children is representative of infection in the population as a whole and schools provide easy access to a large number of children. An important improvement in the new tool is the use of statistical sampling techniques to give NTD programs greater confidence in the decision to initiate or forego MDA.
Ethiopia and Tanzania recently employed the new mapping tool in 55 low-prevalence districts to confirm the findings of the WHO approach, which called for MDA in all 55 districts. The findings from the new tool indicated that 52 districts did not require MDA, saving both countries an estimated $9.2 million in treatment costs.
“This is a cost-effective confirmatory tool that can help countries make the right decisions about whether to initiate treatment in low-prevalence areas,” said Gass. “Our hope is that it will help countries to prioritize treatment in areas with active transmission and conserve precious program resources.”
The confirmatory mapping tool is reported in the Oct. 4 issue of PLOS Neglected Tropical Diseases.